A FLORIDA jury has deadlocked on whether a white man accused of fatally shooting an unarmed black teen in an argument over loud music was guilty of murder.

Jurors convicted Michael Dunn, 47, on three counts of attempted second-degree murder for firing at a vehicle carrying four black teenagers in November 2012.

One of the teens - Jordan Davis, 17 - was killed when he was struck by three of Dunn’s bullets.

Duval County Judge Russell Healey declared a mistrial on the most serious charge - first degree or premeditated murder - for Davis’s death, though Dunn was found guilty on one count of firing a deadly weapon.

The racially mixed 12-person jury could not agree on whether Dunn acted in self defence or deliberately attempted to kill the black teenager.

In testimony Dunn said that he approached the teens, who were in a sports utility vehicle in a gas station parking lot, and asked them to turn down what he described as their loud “thug music.’’ The teens refused, and cursed him.

Dunn said that he feared for his life when one of the teenagers started to get out of the car and come toward him. Dunn pulled a pistol out of his glove box and opened fire.

The software engineer testified that he kept firing as the car drove away, saying he was afraid that he or his fiancee - who had rushed out of the gas station shop when she heard the shots - might get hit by returning fire.

Police found no evidence of a gun in the teens’ vehicle, and the three surviving teenagers testified that they never threatened Dunn.

Dunn said that he only learned that he had shot and killed Davis after seeing a news alert on his phone once he got back to his hotel.

Dunn, who fired 10 times at the car, faces a hefty jail term of at least 60 years. Sentencing is scheduled for March.

The prosecutor, state attorney Angela Corey, said after the verdict that she plans to retry Dunn on the murder charge.

The closely-watched trial has drawn comparisons to the case of neighborhood watch volunteer George Zimmerman, who was last year cleared of killing black teenager Trayvon Martin after claiming self-defence under Florida’s controversial “stand your ground’’ law.

The Dunn verdict also came days after a retired police officer who shot a man for texting in a Florida movie theatre was ordered to be held in prison ahead of trial.

Civil rights activist Al Sharpton joined other critics in decrying the “disappointing verdict.’’

Mr Sharpton, an eminent voice in the uproar that resulted from the Martin case, said the Dunn verdict “clearly does not deal with the fact that a life was lost.’’

Dunn “was convicted of second-degree attempted murder. But he actually killed someone. I think this sends a chilling effect to anybody, particularly people of color,’’ Mr Sharpton told MSNBC television.

Davis’s father said Dunn’s expected long prison term means he will “learn that he must be remorseful for the killing of my son, that it was not just another day at the office.’’

“He was a good kid,’’ Ron Davis told reporters after the verdict.

“There’s a lot of good kids out there... And they should have a voice. They shouldn’t live in fear to walk around the streets worrying about if someone has a problem with somebody else, that if they get shot, it’s collateral damage.’’